Traffic suppression
Traffic suppression aims at controlling traffic rate within an acceptable range by limiting the incoming and outgoing traffic on interfaces. When the rate of incoming broadcast, multicast, or unknown unicast packets exceeds the threshold, the switch discards the packets exceeding the threshold and only allows the packets within the threshold. Take traffic suppression for unknown unicast packets for example. The traffic suppression threshold of unknown unicast packets is 100 pps. That is, the switch allows only 100 packets to pass within one second, and discards the excess packets. If traffic suppression is configured for broadcast, multicast, or unknown unicast packets in the outbound direction, the switch blocks all packets of this type. That is, the interface does not forward packets of this type.
Storm control
Storm control aims at controlling broadcast storms. The switch only controls incoming traffic on interfaces. If the average rate of unknown unicast packets within the storm control interval is higher than the upper threshold, the switch blocks packets on the interface or shuts down the interface according to the configured penalty action. If the interface has been blocked, when the rate of packets received by the interface falls below the lower threshold, the switch unblocks the interface. If the interface has been shut down, you must manually run the undo shutdown command to enable the interface. Take storm control for unknown unicast packets for example. The upper threshold of storm control for unknown unicast packets is 100 pps, the lower threshold is 20 pps, and storm control interval is 5 seconds. If the interface receives more than 500 (100 x 5) packets within 5 seconds, the switch shuts down the interface. The interface can receive packets when its status recovers to Up. Alternatively, the switch blocks all unknown unicast packets on the interface until the next 5 seconds expire. When the number of packets received by the interface falls below 100 (20 x 5), the switch starts to forward the unknown unicast packets on the interface.
For the incoming packets of the same type on an interface, only either of the traffic suppression or storm control can be configured.